This study explored a germplasm collection consisting of 112 Luffa acutangula (ridge gourd) accessions, mainly from Thailand. A total of 2834 SNPs were used to establish population structure and underlying genetic diversity while exploring the fruit characteristics together with genetic information which would help in the selection of parental lines for a breeding program. The study found that the average polymorphism information content value of 0.288 which indicates a moderate genetic diversity for this L. acutangula germplasm. STRUCTURE analysis (ΔK at K = 6) allowed us to group the accessions into six subpopulations that corresponded well with the unrooted phylogenetic tree and principal coordinate analyses. When plotted, the STRUCTURE bars to the area of collection, we observed an admixed genotype from surrounding accessions and a geneflow confirmed by the value of FST = 0.137. AMOVA based on STRUCTURE clustering showed a low 12.83% variation between subpopulations that correspond well with the negative inbreeding coefficient value (FIS = − 0.092) and low total fixation index (FIT = 0.057). There were distinguishing fruit shapes and length characteristics in specific accessions for each subpopulation. The genetic diversity and different fruit shapes in the L. acutangula germplasm could benefit the ridge gourd breeding programs to meet the demands and needs of consumers, farmers, and vegetable exporters such as increasing the yield of fruit by the fruit width but not by the fruit length to solve the problem of fruit breakage during exportation.
Maintenance of genetic diversity within species is a key objective of biodiversity conservation, and small, isolated populations are particularly vulnerable to genetic erosion. Conservation management actions such as predator removal, captive breeding and reintroduction can facilitate numerical recovery of a population, but species often remain at risk from depleted genetic diversity and inbreeding. We investigated dispersal, genetic bottlenecks and genetic population structuring in the island-dwelling Lord Howe woodhen, a species that came perilously close to extinction in the 1970s. Analyses of mark-resighting records and variable genetic markers (single-nucleotide polymorphisms) collected from the contemporary population and 100-year-old museum specimens found strong evidence of restricted dispersal at fine spatial scales, with both the contemporary and historic populations exhibiting strong population structuring between mountain and lowland/slopes sites. Additionally, genetic comparison of the contemporary population and historic specimens demonstrated a decline in genetic diversity over the past century. Specifically for the Lord Howe woodhen, we recommend ongoing genetic monitoring and translocations to increase genetic diversity within the re-established lowland subpopulation. More generally, our results demonstrate how pronounced genetic erosion can arise in species subject to human persecution and predation by introduced predators, and how genetic fragmentation of natural populations can be present at fine geographical scales (less than hundreds of metres). Moreover, without prior information about genetic structure and subsequent genetic monitoring, conservation management can have unexpected negative consequences for the genetic health of populations. Therefore, genetic monitoring and management early in the recovery of populations is desirable to maximize their adaptive potential.